Process for the production of formylcelluloses.



pUNITED STATES mummen.

EMILE BRONNERT, 0F NIEDERMORS CHWEILER, GERMANY, ASSIGNOR TO VERE INIGTE GLANZSTOFF FABRIKEN AKTIENGESELLSCHAFT, 0F 'ELIBERFELD, GERMANY,

PROCESS FOR THE PRODUCTION OF F0RMYLCELL'ULOSE S.

No Drawing.

To all whom 2'15 may concern Be it known that I, EMILE BRoN-Nnn'r, a subject of the German Emperor, residing in Niedermorschweiler, Germany, have invented certain new and useful Improvements in Processes for the Production of F ormylcelluloses, of which the following is a specification.

My invention relates to the formylcelluloses.

It relates particularly to the processset production of forth in my U; S. application, Serial No. 575518, filed August 41-, 1910. In that appliand it can also happen, that, in consequence of interruption in working, defective production, and so forth, sometimes whole charges of finished spinning solution: cannot be spun, yet these must be used to be saved from Waste. From such waste solutions, the

cellulose can be obtained as cellulose hydrate by precipitation and washing, and

without shaping .the same, and this can be treated as the waste cellulose hydrate in the form of threads or" the like is treated, by

simply-dissolving it in concentrated formic acid and preferably under a gentle heat, whereby are obtained valuable formylcellip lose products. Shouldithappen therefore, that ,there was a lack of artificial silk refuse, suitable cellulose hydrates for the productionof formylcellulose may be obtained from such waste solutions. A solution of cellulose in cuprammonia, for example, may be utilized by precipitating the cellulose with alkali or acid, (and without forming into threads) cleansing; freeing from copper, washing and drying. To form fo'rmates, the cellulose hydrate thus obtained is simply placed in formic acid and very gently heated.- A formylcellulose solution is directly obtained. The formic acid employed is preferably the ordinary technical formic acid of 96% concentration.

The cellulose hydrates will dissolve in the formic acid. at ordinary tempera tures,-but that which is preferred is up to Specification of Letters Patent. Application filed April 13, 19 11.

'Seria1No.'620,832. V i t 40 or 50 centigrade. At higher tempera-= temperatures, evaporating the solvent, and

testing-the resultant product as to luster and elasticity.

It it not believed to be best to dissolve the Patented Ma 20, 1913.

cellulose-hydrates too rapidly or to have the f solutions of too high percentage, the best re sults, according to present knowledge, being obtained with a solution of only 6%, produced ata moderate temperature, for ex-' ample 25 centigrade. The formylcellulose.

is then. obtained from the solution by removal of the surplus formic acid, this being preferably accomplished by distilling. the acid at a low temperature'ina rarefied at mosphere, until the desired consistency is reached. By this method the formic-acid serving only as solvent ;may be recovered.

The cellulose hydrate which is obtained according to the pigesent invention by precipitating cellulo's en masse from its solution (and corresponding to waste artificial silk products) cannot be obtained, accords ing to experiments that have been made, by soaking cellulose in cuprammon1a (for example in the proportion of' 1 molecule of cellulose to molecule of copper?, mercerizing cotton with caustic so( a, wash ing and drying. Y

The unfashioned hydrate thus produced forms esters somewhat-more slowly than the regular thread refuse, and produces 'more viscid solutions, without doubt because the cellulose molecule is hydrated still higher,

or in another manner, than the, perhaps, more uniformly driedthreads. Yet these solutions of unfashioned cellulose are very, serviceable, and they can form avaluable substitute for refuse artificial silk-threads and other fashioned waste products for the formation of formylcellulose; The present invention, therefore, relates 'to the treating of unmolded cellulose, apparently ,of a certain degreeof hydration, in place of the 110 acid.

Wlisle products described in the said ,applil loses, which compriscs precipitating m cation, a degree of hydration which is adapted to the, formation of formic acid esters. Tl csc hydrzucs have on examinanccn fonncl to possess a low degree of l lo be weakly h 'clrolyzecl.

.-i.on :ino That is. by liyilraiing is incant the change ellccl'cil by reccplion of water (Hi1) by the cellulose in con'ipounrls similar to incrcerizecl cotton; and by hydrolyzing" is meant the decomposition of the ccllulosc, effected with lllle rcc'cplion of the consl'i'luenls of water 11- O producin a siron lv i 1 c: :3 u

seducing hydro-cellulose.

I chiiui 1. The proccss of producing forinylccllulosses, which comprises subjecting to the action of concentrated formic acid weakly hydrolyzed cellulose hydrates precipitated en cmwse from their solution 4 The process of producing forniylcelluloses, which comprises subjecting to the action of conccnirzitccl acid weakly hydro lyzzccl and weakly hyclruied cellulose hydrates precipitated en masse from their solutions. p

3. The process of producing forlnylcelluloses, which coin 'u'iscs prccipitating weakly hydrolyzccl ccllulose hydrntcsiiom their solulions, and then subjecting the said hy- Grates to the action of conccnllrzitecl formic i. The process of producing forniylcellu- HRI'JSSC weakly hydrolyzed cellulose, hydrates from their solutions, and then subjecting the suirl hyrlrulcs to the sci-ion of concenirulccl formic llClll.

5. The process of producing cellulose iicrnmler'. which comprises prccipitaiing a cnprznninoniu cellulose solution, Washing and drying; the so-forniccl cellulose liyclra'tc, :uul suhjccfing (he sonic lo l'he action of concentrutcd formic acid.

6. T he prccess of producing cellulose lbrinsles, which comprises precipitating an nwssc a cuprsnimonia cellulose solution,

hashing and drying the so-fornied cellulosc hyclraic, and subjecting'thc some to the sciion of concentrated formic acid.

I" V \l I J! l. no process of producing iorinylcelluloses, which comprlses dissolving cellulose in ammonium copper ()Xld, precipitating the cellulose an moose, removing the copper constituents, washing and drying, and then subjecting the cellulose hydrate thus ohluincrl to the action of concentrated formic acid. 7

In witness whereof i. have hereunto signed my name in the presence of two subscribing \vitncsscs.

EM lflL'lfl BRQN NlGR'l.

itnesses CHAS. J, Winona, ALrnnn Hninnn. 

